Screw lifting-jack.



No. 718,431. 1111111112511 JAN. 1a, 1903.

' J. c. 001mm?.

SCREW LIFTING JACK.

APPLIOATIONTILED SEPT. 27, 1902.

1 N0 MODEL.

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NrrnD STATES JAMES C. COVERT, OF WATERVLIET, NEW YORK.

SCREW LlFTlNG-JACK.

SFECIFEGATION forming part of Letters Patent No. 718,431, dated January 13, 1903. Application ledrseptember 27, 1902. Serial No. 125,063. (No model.)

To @ZZ whom it may concern.-

Beit known thatl, JAMES C. COVERT, a citi- Zen-of the United States, residingat Watervliet, in the county of Albany and State of New York, have invented certain new and useful Improvements in Screw Lifting-Jacks, of which the following is aspecication, reference being had therein to the accompanying drawings.

This invention relates to an improvement in lifting-jacks, and the same is embodied in the construction and arrangement of parts presently to be described, and defined in the claims.

The invention relates more particularly to a screw-jack of the right and left handed thread type, although in its useful application it is not necessarily limited to such particular type.

The general object of the invention is the provision of a jack which will possess the requisite strength for lifting heavy loads, such as motor-vehicles and trucks, and which will in its 'structure be proportionately small in dimensions,making it convenient for carrying purposes,while not impairingits strength'.

A further object is to provide a jack with improved means for operating the screw ywherein all complicated parts between the actuating-lever and the screw are dispensed with; also, with means for preventing excessive movement of the screw, whereby the parts may become separated and the jack or load being lifted subjected to injury, and also with detachable sections, which may be readily slipped upon or withdrawn from the upper portion of the jack to give the same the desired vheight to accommodate various conditions.

Novel details of the jack will be apparent upon an inspection of the detailed description hereinafter when read in connection withV the accompanying drawings, forming part hereof, and wherein a preferable embodiment of the invention is illustrated.

In the drawings, Figure l represents a side elevation of the jack possessing my improved features, parts being shown in section. Fig. 2 is an enlarged sectional View of the actuating means and the associated parts. Fig. 3 is a plan view of the actuating means, taken on the linea: of Fig. 1. Fig. 4 is an end view of the actuating-lever, showing' the configuration of the dog carried thereby; and Fig. 5

is a cross-sectional view on the line y y of y Fig. 1 looking toward the upper end of the jack.

Referring more specifically to the drawings, wherein like reference characters refer to corresponding parts in the several views, A designates the supporting-standard or base, formed with a fiat bottom portion a and the strengthening ribs or braces a', the whole being preferably formed integral. This standard has a central longitudinal bore B, the lower portion of which is smooth and the upper portion threaded, as at l), the threads being of the projecting type, whereby an annular 'shoulderb is formed between the threaded and smooth portions of the bore for a purpose which will hereinafter appear.

C designates the threaded stem,the threads of which are conveniently right and lefthanded, respectively, on the upper and lower portions thereof, the lower thread engaging with the standard A, while the upper thread'engages the screw-threaded bore d of the upper supporting member D, said supporting member D being provided with a head or rest E, preferably rectangular in contourand having a seat e formed in its upper surface. The sides of the head are preferably'formed flush with the surface of the supporting member D, the same being of the usual cylindrical formation, whereby extended bearing-surfaces are provided. These bearing surfaces are arranged to fit within and hug the Walls of the rectangular pocket f, formed at the end of the supplemental or extension member F, adapted to be temporarily fitted over the upper end of the member D, the socket being sufficiently deep to secure a firm hold and prevent any lateral tilting of the extension. The upper end of the extension is formed in the same manner and of the same dimensions as the upper member D, so that it willbe obvious that any number of extensions may be nested the one upon the other or substituted one for the other to obtain any desired height of jack.

The type of right or left hand threaded jack is quite ancient in the art, and its advantages are largely those of com pactness and strength. It has, however, been found desirable to have suitable means for actuating the screw without impairing the strength of any of the parts of the jack. It is also desirable to provide such actuating means with as few parts as possible consistent with structural strength and durability. To attain this end,I provide the following means for actuating the jack: Between the threaded portions of the screwstem an enlargement c is provided, and to the lower part of this enlargement is fixedly secured, through the medium of the pin g, a toothed wheel G, the teeth ot' which are formed in its periphery and are vertically arranged. The upper face of this wheel G is smooth and carries a sleeve H, through which a suitable retaining-screw h passes and projects into an annular groove 7L', formed in the upper part of the enlargement. (Best shown in Fig. 2.) By this construction the sleeve H is permitted a free rotary movementaround thescrew-stem, but is prevented from shifting its position either up or down. The sleeve I-I is provided with oppositely-disposed outwardly-extended ears I, Fig. 3, between which is pivoted an operating-lever K, carrying a dog L, projecting downwardly from its inner end and arranged to enter the spaces between the teeth of the wheel G. The lever is secured to the ears by a pivot-pin t' passing therethrough, and the upper surface of the lever is formed approximately straight, so that the same may be elevated into the position shown in dotted lines in Fig. l alongside the upper portion of the jack for convenience in storing or shipping.

In operation, the jack being positioned under the object to be raised, the operating-lever is lowered to throw the dog into engagement with the teeth of the wheel, when a very positive and strong connection is made, and by shifting the handle in a horizontal direction the screw will be actuated to separate or draw together the upper and lower members of the jack to raise or lower the object, as desired.

To facilitate the engagement of the dog with the teeth and its disengagement therefrom with quickness and precision as the operating-lever is raised and lowered, the sides of the teeth M of the wheel G are beveled or tapered perceptibly at their upper ends, as at m, Figs. l and 3, and the dog is beveled or tapered toward its engaging edge, as at Z, Figs. l, 2, and 4. This particular formation of the teeth and the dog insures a ready entrance of the dog between the teeth, the beveled surfaces cooperating to guide the dog into such spaces.

It is necessary that some means be provided to prevent the excessive operation of the screw, so that the parts cannot become accidentally separated, with resultant injury to either the jack or the load. I therefore provide alined apertures n in the standard, through which a pin N may be inserted into 0r removed from a corresponding transverse aperture in the lower screw. The pin is slightly shorter than the diameter of the smooth portion of the bore of the supportingstandard, whereby the same may be freely rotated therein, but is sufficiently long to engage the shoulder b at the lower end of the screw-threaded portion of the bore to limit the upward movement of the screw. The apertures in the standard are approximately the size of the pin, and the advantages incident to the employment of said apertures are many. For instance, they enable the use of4 a loose stop-pin in the screw, inasmuch as the liability of the pin registering with both apertures and being accidentally forced ont of place is but slight, while, on the other hand, when it is desired to insert or remove the pin it will be a very easy matter to cause the pin to register with said apertures. Again, they permit a saving of material, because it the lower portion of the screw be made of a length to project out of the opening in the bottom of the standard for the insertion of the pin such projecting portion is of course waste and in the employment of the jack is more or less annoying, because before the jack could be used the screw would necessarily have to be elevated sulciently far to bring its lower end at least level with the lower surface of the base, and in this particular arrangement the liability of loosening the stoppin is of course increased, as well as that of getting grit and dirt upon the threads of the screw.

It is to be understood that while for the sake of illustration I have shown one embodiment of the invention I, however, do not intend to be limited thereto, because many changes and alterations can be made without departing from the spirit of the invention.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is-

l. In a lifting-jack, the combination with upper and lower portions and a screw between the portions, of a toothed wheel on the screw, a collar rotatably mounted on the screw having projections thereon, a lever horizontally pivoted to said collar, and a dog carried by said lever arranged to engage between the teeth of said wheel, substantially as described.

2. In a lifting -jack of the character described, an operating-screw, a toothed wheel IOO IIO

on said screw, a rotatable collar, a lever pivoted to said collar and arranged to swing vertically, and a dog carried by said lever arranged to engage the teeth of the wheel, substantially as described.

3. In a screw lifting-jack, the combination with an upper and a lower member and an intermediate screw, of actuating means for the screw comprising a member fxedly secured to the screw having outwardly-extending teeth on its edge, a swinging dog rotatably movable on the screw havinga vertical tooth engaging the teeth ofthe fixed meinbeigand an operating-lever connected to said dog, substantially as described.

l. In a screw lifting-jack, the combination with an upper and a lower memberandan intermediate screw, of means for actuating the screw, and a removable extension loosely fitted over the upper end of the upper member, substantially as described.

5. In a lifting-jack of the character described having an upper and a lower member and an intermediate screw, the combination therewith of actuating means for the screw comprising a member iixedly secured to the screw having outwardlyextending teeth on its edge, a rotatable collar on the screw, a vertically-swinging dog pivotally mounted on the collar having a vertical tooth engaging the teeth of the ixed member, and an operating-lever connected to the dog, substantially as described.

6. A lifting-jack of the character described having an upper and a lower member, actuating means, an angular head at the upper end of the upper member, portions of the sides of the head being flush with the surface of said upper member to form an elongated bearingsurface, in combination with a supplemental mem ber or section having a socket adapted to receive said head, substantially as described.

7. A lifting-jack ofthe character described having a lower member, a cylindrical upper member, actuating means, an angular head at the upper end of the upper member, portions of the sides of said angular head being flush with the surface of said upper member, and constituting elongated bearing-surfaces, in combination with asupplemental member or section having a socket adapted to receive said head, substantially as described.

8. A lifting-jack ofthe character described having a lower member and an upper member, actuating means, and a head on the upper member, in combination with a supplemental member or section having a socket adapted to loosely it over said head, substantially as described.

9. A lifting-jack of the character described having a lower member and an upper member, actuating means, and a head on the up per member, in combination with a supplemental member or section having a socket adapted to loosely t over said head and a head similar to the head of the upper member, whereby a plurality of supplemental members or sections may be interchanged or nested, substantially as described.

lO. In a lifting-jack of the character described, an'operating-screw, a toothed wheel on said screw, the sides of the teeth of said wheel being beveled or tapered at one end, and means for rotating said wheel including a pivoted dog adapted to enterthe spaces between the teeth, the beveled sides of the teeth facilitating the entrance of the dog therebetween, substantially as described.

l1. In a lifting-jack of the character described, an operating-screw, a toothed Wheel on said screw, the sides of the teeth of said wheel being beveled or tapered at one end, and means for rotating said wheel including a pivoted dog having beveled or tapered sides,

and means for rotating said wheel including a dog pivoted to swing vertically and adapted to enter thepspaces between the teeth, the beveled sides of the teeth facilitating the entrance of the dog therebetween, substantially as described.

13. In a lifting-jack of the character described, an operating-screw, a toothed wheel on said screw having vertically disposed teeth, the sides of the teeth of said wheel being beveled or tapered and means vfor rotating said wheel including a pivoted dog adapted to swing vertically and enter the spaces between the teeth, the beveled sides of the teeth facilitating the entrance of the dog therebetween substantially as described.

14. Alifting-jack of the character described having a lower member and an upper member, said lower member having a longitudinal bore screw-threaded at its upper end and smooth at its lower end, a shoulder arranged between the screw-threaded and the smooth portions of the bore, an operating-screw engagin g the screw-threaded portion of the lower member, and means for limiting lthe upward movement of the screw comprising a removable stop projecting laterally from the lower end of the screw and arranged to be rotated' with the screw in the smooth portion of the bore and to contact with the shoulder below the screw-threaded portion thereof, substantially7 as described.

15. A lifting-jack of the character described having a lowermember and an upper member, said lower member having a longitudinal bore screwthreaded at its upper end and smooth at its lower end, a shoulder arranged between the screw-threaded and the smooth portions of the bore, an operating-screw engaging the Iscrew-threaded portion of the lower member, and means for limiting the upward movement of the screw-comprising a pin passing transversely through the lower end of the screw and arranged to be rotated with the screw in the smooth portion of the bore and to contact with the shoulder below the screw-threaded portion thereof, and said lower member being provided with alined apertures at a point above its base for the insertion or removal of the pin, substantially as described.

16. In a lifting-jack of the character described, an operating-screw, a wheel on said screw having teeth on its periphery, a rotata- IOO IIO

ble collar, a dog carried by the rotatable collar adapted to swing vertically thereon and arranged to engage the teeth of the wheel, and actuating means for the dog; substantially as described.

17. In a lifting-jack, the combination with upper and lower portions and a screw therebetween, of a toothed Wheel on the screw, a collar rotatably mounted on the screw, projections on the collar, a dog carried by the rotatable collar adapted to swing vertically between the projections thereof and arranged to engage the teeth of the Wheel, and actuating means for the dog; substantially as described.

18. In a lifting-jack of the character described, an operating-screw, a Wheel on said screw provided with an approximately vertically disposed tooth, a dog having an ap proximately vertically disposed tooth arranged to engage the tooth of the Wheel, an actuating-lever for the dog, means whereby said lever may be moved in a horizontal direction, and a horizontal pivot pin passing` through the lever upon which the same may be raised and lowered; substantially as and for the purpose described.

19. In a lifting-jack of the character described, an operating-screw, a Wheel on said screw provided with an approximately vertically disposed tooth, a dog having an approximately vertically disposed tooth arranged to engage the tooth of the Wheel, means whereby the dog may be moved in a horizontal direction, an actuating-lever for the dog, and a horizontal pivot upon which the dog and its actuating-lever are mounted whereby they may both swing iu a vertical direction; substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JAMES C. COVERT.

Witnesses:

EDWARD I-I. YOUNG, L. S. BACON. 

